drm/stm: attach gem fence to atomic state

[ Upstream commit 8fabc9c3109a71b3577959a05408153ae69ccd8d ]

To properly synchronize with other devices the fence from the GEM
object backing the framebuffer needs to be attached to the atomic
state, so the commit work can wait on fence signaling.
Signed-off-by: NAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NPhilippe Cornu <philippe.cornu@st.com>
Tested-by: NPhilippe Cornu <philippe.cornu@st.com>
Signed-off-by: NBenjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190712084228.8338-1-l.stach@pengutronix.deSigned-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/gpu/drm/stm/ltdc.c

@@ -19,6 +19,7 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_of.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_plane_helper.h>
@@ -825,6 +826,7 @@ static const struct drm_plane_funcs ltdc_plane_funcs = {
 };
 
 static const struct drm_plane_helper_funcs ltdc_plane_helper_funcs = {
+	.prepare_fb = drm_gem_fb_prepare_fb,
 	.atomic_check = ltdc_plane_atomic_check,
 	.atomic_update = ltdc_plane_atomic_update,
 	.atomic_disable = ltdc_plane_atomic_disable,